Showing papers by "North Eastern Regional Institute of Science and Technology published in 2015"

Development of Decadal (1985–1995–2005) Land Use and Land Cover Database for India

Abstract: India has experienced significant Land-Use and Land-Cover Change (LULCC) over the past few decades. In this context, careful observation and mapping of LULCC using satellite data of high to medium spatial resolution is crucial for understanding the long-term usage patterns of natural resources and facilitating sustainable management to plan, monitor and evaluate development. The present study utilizes the satellite images to generate national level LULC maps at decadal intervals for 1985, 1995 and 2005 using onscreen visual interpretation techniques with minimum mapping unit of 2.5 hectares. These maps follow the classification scheme of the International Geosphere Biosphere Programme (IGBP) to ensure compatibility with other global/regional LULC datasets for comparison and integration. Our LULC maps with more than 90% overall accuracy highlight the changes prominent at regional level, i.e., loss of forest cover in central and northeast India, increase of cropland area in Western India, growth of peri-urban area, and relative increase in plantations. We also found spatial correlation between the cropping area and precipitation, which in turn confirms the monsoon dependent agriculture system in the country. On comparison with the existing global LULC products (GlobCover and MODIS), it can be concluded that our dataset has captured the maximum cumulative patch diversity frequency indicating the detailed representation that can be attributed to the on-screen visual interpretation technique. Comparisons with global LULC products (GlobCover and MODIS) show that our dataset captures maximum landscape diversity, which is partly attributable to the on-screen visual interpretation techniques. We advocate the utility of this database for national and regional studies on land dynamics and climate change research. The database would be updated to 2015 as a continuing effort of this study.

Applications of ligninolytic enzymes to pollutants, wastewater, dyes, soil, coal, paper and polymers

Abstract: The breakdown of plant lignin modifies the structure of lignocelluloses, thus making carbohydrates accessible for efficient bioconversion. White-rot fungi produce ligninolytic enzymes such as lignin peroxidase, manganese peroxidase, laccases and various peroxidases, which mineralize lignin efficiently. We review here applications of ligninolytic enzymes for the delignification of lignocellulosic materials, the removal of recalcitrant organic pollutants, wastewater treatment, decolorization of dyes, soil treatment, conversion of high molecular weight coal fractions to low molecular weight coal fractions, which could be used as a feed stock for the production of commodity chemicals, biopulping and biobleaching in paper industries and enzymatic polymerization in polymer industries.

Reference evapotranspiration under changing climate over the Thar Desert in India

Abstract: Reference evapotranspiration (RET) plays a critical role in irrigation planning and is needed for the determi- nation of water demands of crops. Thus, in the present study, trends in RET were identified over Bikaner located in the Thar Desert (Rajasthan) in India using the non-parametric Mann-Kendall (MK) test. First, RET values were estimated through the Penman-Monteith method for different time scales using meteorological data for 39 years from 1967 to 2005. Second, the effect of significant lag-1 serial correlation was removed from the time series of RET by pre-whitening. Third, trends were investigated using the MK test. RET was found to decrease significantly at Bikaner during annual, pre-monsoon, monsoon and post-monsoon time scales. On probing the causal meteorological parameters responsible for the observed RET trends in the Thar Desert, it was witnessed that wind speed dynamically influenced the observed RET changes at the annual time scale and all the four seasons over the Thar Desert. The maximum temperature, followed by relative humidity, influenced the RET trends at annual and seasonal (winter, pre-monsoon and monsoon) time scales. The calm atmosphere witnessed over this arid site substantiates RET decreases over this Thar Desert site. The results of this study support that the evapotranspiration decreases over Bikaner are controlled mainly by trends in the aerodynamic component, i.e. by the effects of significant wind speed decreases on RET, than the changes in the radiative component over the arid site located in the Thar Desert.

Influence of Lime on Shrinkage Behavior of Soils

Abstract: Damage due to soil shrinkage is a serious problem in many parts of the world. Lime can significantly improve the performance of soils, both in terms of increase in strength and reduced swelling. However, its efficacy in reducing shrinkage of soils has not been studied much. A series of experiments were conducted to develop an understanding of the shrinkage behavior of lime-treated soils. Six different soils covering wide range of plasticity were treated with varied percentage of lime and curing period. Lime increases the shrinkage limit of soils irrespective of their plasticity characteristics; however, it is more in case of high plastic soils than the low plastic ones. Volumetric shrinkage continued to reduce until about 5% of lime content beyond which further reduction was marginal. Hence 5% of lime can be considered as the optimum lime content giving maximum shrinkage reduction. With lime the shrinkage responses of soils were found to have grown flatter indicating that lime can effectively redu...

Extended Period Simulation of Pressure-Deficient Networks Using Pressure Reducing Valves

Abstract: Generally, the water distribution networks are designed for peak demands so that under normal operating conditions pressure is adequate to meet the nodal demand however, due to this, the pressure remains excessive when the consumption is low. This leads to huge water leakages and pipe bursts due to excess available pressure. These excess of pressure can be reduced by operating pressure reducing valves. Moreover, the pressure deficient conditions of water distribution network depends on many factors such as excess demand (i.e., fire fighting demand), location and elevation of nodes, location and pressure setting values of pressure reducing valve, ageing of pipes (i.e., increase the pipe roughness) etc. In exceptional situations, pressure deficient condition also may occur when there is a fire demand while pressure reducing valves are in operating condition. The available literature of the pressure deficient condition as well as optimal location, number and their pressure setting values of pressure reducing valves are analysed by mathematical programming or optimization methods. Normally, it is cumbersome to the field engineers to use the any toolkit utility functions. Hence in this study, the pressure deficient condition is analysed via the method of modified pressure-deficient network algorithm without using EPANET toolkit functions which are coupled with pressure reducing valve operation. A benchmark problem is analysed and compared for the proposed method. Further, a real water distribution networks is analysed introducing fire demand at junction/distribution node using fixed and diurnal nodal demand pattern coupled with and without pressure reducing valve operation in a single hydraulic simulation.

Threats and conservation of Paris polyphylla an endangered, highly exploited medicinal plant in the Indian Himalayan Region

Abstract: Paul A, Gajurel PR, Das AK. 2015. Threats and conservation of Paris polyphylla an endangered, highly exploited medicinal plant in the Indian Himalayan Region. Biodiversitas 16: 295-302. The Indian Himalayan Region is home of numerous globallysignificant medicinal plants. Paris polyphylla Smith is an important medicinal perennial herbaceous species used mostly in traditionalmedicine, having medicinal properties like anticancer, antimicrobial, antioxidant, anti-tumor, cytotoxicity, steroid saponins etc. Thepresent study highlights the uses, population status and threats to P. polyphylla in Arunachal Pradesh. P. polyphylla is distributed intropical to temperate region of South East Asia, particularly in Bhutan, China, India, Laos, Myanmar, Nepal, Thailand and Vietnam. InIndia it is distributed in the state of Arunachal Pradesh, Himachal Pradesh, Jammu and Kashmir, Manipur, Meghalaya, Mizoram,Nagaland, Sikkim and Uttarakhand. In the Eastern Himalayan state of Arunachal Pradesh, the species found to be occurring with distinctmorphological interspecific variations. In the past 5 years the market demand of the species increased tremendously, which ultimatelyled to the over exploitation of the species and traded illegally in heavy quantities. The present study showed very poor populationdensity, which ranged between 0.42 individuals m-2 to 1.48 individuals m-2. While, Importance Value Index of the species rangedbetween 3.37 to 8.45. Because of the unsustainable extraction and poor natural regeneration of the species, wild populations are at riskof extinction and accordingly it has been listed as an endangered species. The rhizome is the primary mode of regeneration, although itregenerate from seeds. Because of the commercial demand of the rhizome, the population of the species may entirely be wiped out ifproper conservation initiatives have not been taken. Effective conservation strategies both in situ and ex situ may help to protect thespecies from its extinction. Inclusion of the species under the priority species list of both the National and State Medicinal Plant Boardsfor cultivation may be helpful for its long term management and conservation. Mass awareness and active involvement of local peoplefor large scale cultivation may reduce the pressure on wild populations. This will meet the market demand and boost the rural economyand will also help in conservation of the species.

Probability-based controlled flooding in opportunistic networks

Abstract: Opportunistic networks (Oppnet) are challenged networks in present wireless communication scenario. These networks are mainly applied to situations where a persistent end-to-end path between the source and the destination does not exist. Delay/Disruption Tolerant Networking (DTN) is mostly used to solve this end-toend path problem in such networks. Many routing protocols have been proposed in literature that consider various performance metrics such as delivery delay, packet delivery rate, hop count, among others. In this paper, a new routing protocol named as PRoWait has been designed which can overcome the shortcomings of the already existing protocols in Oppnets. The proposed protocol also incorporates the merits of existing protocol so that it can be reliable and efficient for the communication of pedestrians with handheld devices. Simulation results obtained for the proposed scheme show better performance as compared to the Porphet, Spray and Wait and Epidemic routing protocols in terms of packets delivery probability, overhead ratio, and hop count performance metrics.

Towards virtual ergonomics: aviation and aerospace

Abstract: Purpose – The purpose of this paper is to highlight state-of-the-art digital human modeling applications in aviation and aerospace industry, generate research interest and promote application of digital human modeling technology among audience of diverse background including researchers, students, trainees, etc. in academia and industry; designers; engineers; and ergonomists associated with aviation and aerospace sectors. Design/methodology/approach – Comprehensive literature search was performed and, subsequently, all publications identified were studied thoroughly at least by abstracts. Available information has been segregated under different headings and depicted systematically for easy understanding by readers. Findings – Virtual human modeling technology has been used in assessing reach and accessibility in aircraft cockpits, creating accurate posture libraries, performing vision analysis for pilots, determining design modifications to accommodate female users, predicting probable pilot behavior in ...

Power quality analysis of hybrid renewable energy system

Abstract: An hybrid renewable energy sources consisting of solar photovoltaic, wind energy system, and a microhydro system is proposed in this paper. This system is suitable for supplying electricity to isolated locations or remote villages far from the grid supply. The solar photovoltaic system is modeled with two power converters, the first one being a DC-DC converter along with an maximum power point tracking to achieve a regulated DC output voltage and the second one being a DC-AC converter to obtain AC output. The wind energy system is modeled with a wind-turbine prime mover with varying wind speed and fixed pitch angle to drive an self excited induction generator (SEIG). Owing to inherent drooping characteristics of the SEIG, a closed loop turbine input system is incorporated. The microhydro system is modeled with a constant input power to drive an SEIG. The three different sources are integrated through an AC bus and the proposed hybrid system is supplied to R, R-L, and induction motor loads. A stati...

Metalloisoporphyrins: from synthesis to applications.

Abstract: An overview of the chemistry of isoporphyrin, the tautomer of porphyrin, whose existence was predicated by the Noble laureate Woodward, is presented with emphasis on hydroxy-isoporphyrins of tetra-aryl derivatives. The chemistry of metalloisoporphyrin has been discussed since the discovery of the first metallo-isoporphyrin by Dolphin and co-workers, as no comprehensive article is available on this beautiful macrocycle. Attention is paid to the possible applications of metalloisoporphyrins as photosensitizers in photodynamic therapy, as a near infra-red dye and as a reactive agent for different atom transfer reactions. Some important findings about reactivity and theoretical results of hydroxy-isoporphyrins are discussed. Furthermore, the approaches of heme oxidation via isoporphyrin as an intermediate to understand the heme oxygenase mechanism are discussed. The metalloisoporphyrins are discussed reviewing coordination modes, structural changes, electronic properties and biological relevance.

Predicting Suitable Habitats for the Vulnerable Eastern Hoolock Gibbon, Hoolock leuconedys, in India Using the MaxEnt Model

Abstract: The eastern hoolock gibbon, Hoolock leuconedys, is categorized as Vulnerable on the IUCN Red List and assessed as a Schedule I species of the Wildlife (Protection) Act of 1972 in India. We predict the potential habitat of H. leuconedys in the state of Arunachal Pradesh, India, using the Maximum Entropy (MaxEnt) distribution modelling algorithm. The model was developed using 90 known localities of H. leuconedys in the state. Nineteen environmental parameters along with 12 normalized difference vegetation index (NDVI) layers, elevation and land use and land cover (LULC) were used in the modelling. Amongst the environmental input variables, the precipitation of the coldest quarter (BIO 19) had the highest contribution to the model (26.03%) and the twelve NDVI layers collectively contributed 60.91%. Two districts, Lower Dibang Valley and Lohit, which are known to contain H. leuconedys, occupied 64.75% of the predicted distribution area of the species. Thus, we aid in the identification of suitable areas for the reintroduction program of H. leuconedys that is planned by the Gibbon Conservation Breeding Centre, Biological Park, Itanagar, Arunachal Pradesh, India.

In vitro study on antioxidant activity and phenolic content of three Piper species from North East India

Abstract: The antioxidant activities of water (W) methanol (ME), water: methanol (1:1), ethanol (ET), chloroform (CH), ethyl acetate (EA) and petroleum ether (PE) extracts of the leaf of three Piper species viz; Piper betle L, Piper betleoides C.DC and Piper wallichii (Miq.) Hand-Mazz was investigated using several in vitro antioxidant assays. The scavenging activity was evaluated by using DPPH (2,2′-diphenyl-1-picryl hydrazyl), FRAP (ferric reducing antioxidant power), ABTS [2,2-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid)], hydrogen peroxide scavenging, hydroxyl radicals scavenging, chelating power and reducing power assay. These methods were used for evaluating the best solvent system for extracting the antioxidants. The total phenolic content (TPC) and total flavonoid content (TFC) were also determined for all the extract. The phenolic acid and flavonoids i.e. catechin, quercetin, gallic acid, coumaric acid and protocatechuic acid which may be responsible for antioxidant activity in the fraction of best solvent system were evaluated. The catechin found to be higher (>1.1 mg/g) in all the species in water: methanol extract. The study revealed that Piper species may be used as one of the source of potential antioxidants.

Vibrational studies of polar aprotic molecule in aromatic chemical and isotropic solvents: experimental and quantum chemical investigations

Abstract: Raman spectroscopic technique has been used to study the intermolecular interactions and dynamics of SO, C―H and CSC stretching modes of dimethyl sulfoxide (DMSO) in binary mixtures using methyl benzene (MBN) and deuterated methyl benzene (MBNd) aromatic solvents. The Raman band of SO stretching mode has been deconvoluted into four distinct bands for neat DMSO as well as in binary mixtures. Deconvoluted bands in neat DMSO were assigned as monomer, cyclic out-of-phase, cyclic in-phase and chain dimers having peak wavenumbers 1069.10, 1056.60, 1041.50 and 1027.30 cm−1 respectively. Peak wavenumber of SO stretching mode shows red shift, while peak wavenumbers of C―H and CSC stretching modes show blue shift with the increase in solvent concentration. The vibrational relaxation phenomena for all the stretching modes have been studied as a function of solvent concentration. Quantum-chemical calculations have been carried out to gain more insight into the self-association of DMSO and in interacting environment with the solvents using ab initio and density functional theory method. The ab initio basis set is HF/6-31 + G (d, p) for the interacting system. The hydrogen bond complexes of DMSO with MBN and MBNd using IEF-PCM model have been calculated using B3LYP functional and 6-31 + G(d,p) basis sets. Theoretical calculations have been compared with the experimental findings and we obtained good coherence of the results. Copyright © 2015 John Wiley & Sons, Ltd.

Analysis of the effect of electric field due to High Voltage Transmission lines on humans

Abstract: The electromagnetic radiations from High Voltage Transmission lines are causing serious health threats to human beings working outdoors. Interference from HV lines may be electrostatic and electromagnetic interference. Probable risk for leukemia, neuropsychological disorders, cancer and reproductive outcomes has been reported due to this exposure. This paper is aimed at analysis of electric field distribution in a 400kV transmission line. Electric Field is calculated using FEM based ANSYS software package. By comparing these values with the standard available guidelines and the values calculated by analytical method we can find the permissible distance that the human beings may be exposed to.

Simulation of synchronous reference frame PLL based grid connected inverter for photovoltaic application

Abstract: Utilization of renewable energy resources have been the most important & prospective field to seek new energy sources to meet up the increasing demand in power all over the world specially in a developing country like India. Grid-connected photovoltaic systems are providing a viable technology for producing electrical energy by using renewable energy resources. High power density, high efficiency and reliability for this system are important design considerations along with control objectives like Maximum power point tracking (MPPT), grid synchronization, islanding detection and prevention, sinusoidal current injection into the grid, maintaining the THD within certain permissible limit (<5%), active harmonic filtering, EMI/EFI protection. This paper present a double stage converter with some ancillary features, where in the first stage, dc-dc boost conversion is achieved. Second stage dc-ac inversion is achieved using voltage source inverter. Grid synchronization is achieved by using synchronous reference frame base Phase locked loop (SRF PLL), whose performance is equally good for all the frequencies unlike the normal PLL. PI controller will be used in the current and the voltage controller.

Effects of elastic seats on seated body apparent mass responses to vertical whole body vibration

Abstract: Apparent mass (AM) responses of the body seated with and without a back support on three different elastic seats (flat and contoured polyurethane foam (PUF) and air cushion) and a rigid seat were measured under three levels of vertical vibration (overall rms acceleration: 0.25, 0.50 and 0.75 m/s2) in the 0.5 to 20 Hz range. A pressure-sensing system was used to capture biodynamic force at the occupant-seat interface. The results revealed strong effects of visco-elastic and vibration transmissibility characteristics of seats on AM. The response magnitudes with the relatively stiff air seat were generally higher than those with the PUF seats except at low frequencies. The peak magnitude decreased when sitting condition was changed from no back support to a vertical support; the reduction however was more pronounced with the air seat. Further, a relatively higher frequency shift was evident with soft seat compared with stiff elastic seat with increasing excitation.

Habitat Characteristics and Their Effects on the Density of Groups of Western Hoolock Gibbon (Hoolock hoolock) in Namdapha National Park, Arunachal Pradesh, India

Abstract: Understanding the relationship between a species and its habitat is crucial for conservation action planning. The Endangered western hoolock gibbon (Hoolock hoolock) has a fragmented distribution in northeast India, Bangladesh and parts of western Myanmar. Namdapha National Park in Arunachal Pradesh contains the largest population of western hoolock gibbons in India. We carried out an auditory sampling survey and habitat analysis of western hoolock gibbons in the park from September to December 2012 in three potentially suitable forest types: tropical broad-leaved forest, tropical wet evergreen forest, and wet temperate forest. A new method of analysis of singing frequency revealed that only 21–23% of groups sing per day. Group detectability declined sharply beyond a listening radius of 600 m. Auditory sampling across 15 listening areas revealed an estimated mean density of 3.65 groups km−2. We found no significant differences in density among forest types. The habitat study revealed a total of 122 species of trees (girth at breast height ≥30 cm) in the three forest types, representing 73 genera in 41 families, with the highest number of tree species in wet evergreen forest (93) followed by tropical broad-leaved forest (52) and wet temperate forest (40). None of the vegetation traits we measured (mean canopy cover, girth, density, and total basal area of all trees) and no habitat disturbance factors correlated significantly with gibbon density. This lack of correlation may have been due to the prevailing anthropogenic effects that adversely affected gibbons and their habitat, such as forest degradation, road widening, and hunting, overriding the relatively smaller natural variation in vegetation. This study adds to our knowledge of the habitat requirements of hoolock gibbons and indicates that Namdapha National Park is more important to conservation of the western hoolock than previously thought.

Evaluation of Dust Exposure among the Workers in Agricultural Industries in North-East India.

Abstract: This study aims to quantify dust exposure among the workers in four different industrial settings: rice mills, flour mills, oil mills, and tea factories and to compare the obtained data with the permissible exposure limit (PEL) of Indian Union Ministry of Labour as well as to compare the dust exposure across activities and seasons. RespiCon(TM) particle sampler was used for collecting dust concentration in the breathing zone of the workers. In total, 149 workers participated in the study and 204 samples were collected. Samples were collected in the vicinity of different processing operations. Samples in the rice mills were collected for two consecutive years in two seasons; however samples from other industries were collected for 1 year. The results indicate that geometric mean (GM) of dust exposure was significantly (P < 0.0001) different among industrial settings. Respirable dust were 8.22, 5.76, 2.98, and 6.34mg m(-3) and total dust exposure were 81.05, 111.02, 56.68, and 39.85mg m(-3) in the rice mills, oil mills, flour mills, and tea factories, respectively. Considerable variations in dust exposure were observed in different activities in the rice and oil mills; however variation was relatively less in the flour mills and tea factories. In the rice mills, dust concentration was higher in winter than those obtained in autumn and it is significantly different (P < 0.05) for inhalable dust and total dust. Positive correlation was obtained in thoracic dust (r (2) = 0.94) and inhalable dust (r (2) = 0.97) with total dust and thoracic dust with inhalable dust (r (2) = 0.89). The results show that majority of the workers are exposed to higher level of respirable dust as compared to the PEL, while total dust exposure to all the workers were higher than the PEL; thus, immediate reduction of dust exposure among the workers is necessary for preventing respiratory system impairment.

Performance of digital modulations over TWDP fading channel

Abstract: The outage and average symbol error rate of a single channel system are analyzed over two-wave diffused power (TWDP) fading channels. An expression of characteristic function and outage probability of signal-to-noise ratio (SNR) for TWDP fading channel have been derived. Probability distribution function based approach has been followed to derive expressions of average symbol error rate for different coherent and noncoherent M-ary modulation schemes. Effects of the types of modulation and the fading parameters K and A on the system performance have been studied. The results obtained are verified with the special case results available in literature and by Monte Carlo simulation.

Capacity analysis of MRC receiver with adaptive transmitters over TWDP fading channels

Abstract: For arbitrary branch Maximal Ratio Combining (MRC) diversity system over Two Wave Diffused Power (TWDP) fading channel, the channel capacity equations for adaptive transmission techniques are obtained. The capacity expressions are derived using the probability density function (PDF) expression of the output signal to noise ratio of MRC receiver. The effects of fading parameters K and Δ and diversity order, M, on the system capacity are evaluated for different adaptive transmission techniques. A comparison of the capacities for the various adaptive transmission schemes employed with MRC receiver over TWDP fading channel is also presented.

Capacity of dual MRC with adaptive transmitters over non-identical TWDP fading channels

Abstract: One of the significant indicators of the Quality of Service that can be achieved by a wireless communication system is the findings of capacity analysis. Hence, these results are of enormous significance to wireless communication system designers and engineers. Channel capacity expressions for dual branch Maximal Ratio Combining (MRC) diversity system with various adaptive transmission techniques over two wave diffuse power (TWDP) fading channels are derived. The probability density function (PDF) based method is applied for the derivation of these capacity expressions. The consequences of fading parameters K and Δ and diversity order M, on the capacity of MRC receiver with different adaptive transmission techniques have been examined. Finally, a comparison of the capacity of the receiver with various adaptive transmission schemes over TWDP fading channel is also presented.

Voltage stability analysis using Lyapunov energy function

Abstract: Power system is a typical nonlinear system and voltage stability is an important subject of power system stability. Lyapunov energy function is an important tool for the determination of stability for nonlinear systems without the need to find exact solution. In this paper, the voltage stability of a single machine infinite bus (SMIB) system is analyzed using Lyapunov's energy function obtained by variable gradient method. Various energy curves for different equilibrium points based on the variation in load angles are obtained which clearly reflects the change in energy content of the system and load voltage in the system.